Present day metallurgical processes involving extensive use of oxygen are characterized by generation of high temperatures and corrosive effect of the molten slag, the metal and the gas atmosphere on the refractory lining of the metallurgical set and, particularly, on the lining of the casting ladles. In addition, a non-uniform distribution of thermal loads over the lining surface of the casting ladles results in local lining damages, and the failure of even a single unit of the lining invariably causes a shutdown of the metallurgical set for long-term repair.
To prolong the life of the refractory lining and to provide for stable operation of the metallurgical plant, a great emphasis is placed in maintenance both in the cold and hot conditions.
One of the most advanced methods of repairing the lining of the metallurgical plants is guniting which enables the repair of the lining surface to be performed both in the cold condition and at high temperatures.
The basic nature of the guniting process is coating of the lining surface to be repaired with a moistened granular mixture. The gunite is laid on the damaged areas in thin uniform layers by means of special devices called cement guns from which the gunite is delivered by compressed air along a hose provided with a nozzle at its end, and is deposited by the imparted kinetic energy onto the surface to be repaired.
The present day devices for guniting the casting ladles are very labor consuming, since for repairing the lining of the ladle the repairman has to control the nozzle manually, not infrequently within the ladle where the temperature reaches the level of 80.degree. to 100.degree. C., in an extremely dusty atmosphere.